first off *hugs*...I'd want to scream too if I were in your shoes.
second, print out all those lovely emails and keep them for future reference. You never know when they'll come in handy...don't need to read them, just print, file away and ignore (can you tell I'm in the midst of a legal battle? Document document document!).
third, absolutely involve a third party in this if the said third party is volunteering. You don't have to go into sordid details with this person; just the facts and what you need this person to do. It's OK to lean on friends at times like these. AND, bonus, your STBX may well behave himself when he receives his stuff from your best friend instead of from you. My XAH was all for being mean and abusive to me, but when faced with my family and friends, he was a little shameful kitten.